Method and apparatus for spraying insulation



Nov. 4, 1969 w. ECKERT METHOD AND APPARATUS FOR SPRAYING INSULATION Filed Aug. 14, 1967 INVENTOR LEWIS W. ECKERT ATTORNEY United States Patent O 3,476,318 METHOD AND APPARATUS FOR SPRAYING INSULATION Lewis W. Eckert, Lancaster, Pa., assignor to Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania Filed Aug. 14, 1967, Ser. No. 660,310 Int. Cl. B05b 7/06, 7/14 US. Cl. 239-10 2 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for spraying insulation wherein the dry spray-type fiber insulation is treated with water in a special nozzle structure to secure the application and adherence of the insulation to its support surface. The nozzle structure uses an internal spray to prewet the insulation to eliminate dust an external water spray to wet and direct the insulation into position.

BACKGROUND OF THE INVENTION Field of the invention The invention is directed to a nozzle structure for the Wetting and directing of a dry material which is to be used as an insulating coating. Furthermore, the invention is directed to a method of applying dry insulation to eliminate dust and secure a thick buildup of insulating material.

Description of the prior art The most commonly used spray insulating nozzle for applying spray insulation is the external nozzle produced by the Universal Insulating Machine Company. This nozzle is called an external nozzle because a plurality of small apertures around the periphery of the exit end of the nozzle direct a stream of water outwardly from the nozzle exit in the direction the insulation is being sprayed. The water is directed as an envelope around the supply of spray insulation exiting from the nozzle, or the water may be directed as an envelope around the insulating material and partly as a spray directed inwardly towards the insulating material to wet the material. This external nozzle is used primarily for the depositing of a large volume of spray fiber insulation to a layer thickness of 6" to 8".

A second nozzle commonly used in the art is an internal nozzle. This nozzle is also made by the Universal Insulating Machine Company. The nozzle has a waterring spaced inside the nozzle rearwardly from the exit of the nozzle to provide a solid curtain of water through which material will pass. The end of the nozzle has a Tefion tube to provide control of the spray pattern. This nozzle is used primarily with insulating cement.

A fiber insulation is composed of at least 75% long fibers of asbestos or mineral wool with its remaining composition being binders such as clay and cement. An insulating cement has a much larger percentage of the binders, such as clay and cement, and utilizes short fibers as its remaining component. The insulating cement does provide a small degree of insulation, but is used primarily to provide a smooth finish coat over the fiber insulation "ice and is normally applied only to a A" or /2" thickness. The fiber insulation is the primary insulator and is normally applied to a thickness of 6" to 8". Since the internal nozzle is used primarily to apply the insulating cement, it is applying a much wetter material to form a much denser coat than you secure with the fiber insulation.

The internal nozzle has, in some cases, been used to apply the fiber insulation; however, when used with the fiber insulation, the fiber tends to be discharged as surges of globs of material. When the insulation is applied in this manner, it is much wetter than necessary and tends to compact to a higher degree. Consequently, it lacks the adhesion that is necessary to build up thick layers of 6" to 8".

When the external nozzle is used to apply fiber insulation, there is an acute dust problem which cannot be controlled by manipulation of the controls for the external nozzle. Use of the internal nozzle with a fiber insulation tends to diminish the dust problem, but this results in a sacrifice in the thickness of the insulating coat that can be provided. Also, the coat that is provided tends to have a lower insulating value, and unless the nozzle is carefully regulated, the nozzle structure tends to clog with the fiber insulation. The internal nozzle is best used for applying only insulating cement. The problem that the industry is attempting to overcome is that of securing a reduction in dust while still maintaining the capability of providing a thick coating of fiber insulation. To date, the pror art is capable of only providing one of these features with a sacrifice of the other feature.

SUMMARY OF THE INVENTION The invention is directed towards the method and apparatus -for depositing spray insulation without a dust problem. Specifically, the invention is directed towards a novel nozzle structure which permits the securing of the desired end results.

The nozzle structure has two water injection areas which combined eliminate the dust problem and permit the proper deposition of the spray insulation to the desired thickness. Spaced rearwardly from the exit opening of the spray nozzle is the first water injection area. This area is actually a water mist curtain through which the dry spray insulation is passed to permit the initial prewetting of the insulation. This particular water bath contributes greatly to the reduction of the dust problem.

The second water injection area is at the exit of the nozzle structure. Here a water envelope is placed around the spray insulation as it exits from the nozzle structure. Also, some water may be directed into the stream of spray insulation. The water injection at this point is used primarily for the control of the spray insulation and to provide it with the wetness that is necessary to give the spray insulation the adhesion necessary to permit the buildup of insulation.

Both water injection areas are subject to manual control by the operator. This permits the nozzle to be utilized with many difierent brands of spray insulation which vary to a slight extent. The operator need only adjust his two water injection areas to provide the proper balance between the two, so that dust control and proper application of the spray insulation may be balanced to permit the nozzle to carry out its intended functions.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a front view of the nozzle assembly; and FIGURE 2 is a cross sectional view of FIGURE 1 along line 22.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGURE 2, the nozzle assembly 2 is connected to a supply hose 4. The supply hose is connected to the conventional fiber spraying machine which causes the dry fiber insulation to be pneumatically conveyed to and through the nozzle structure toward the subject matter which is to be coated with the insulating fibers.

The fibers passing through the nozzle are first engaged by a water mist bath generated by the water mist assembly 6. The assembly consists of a hose 8 which feeds water through a control valve 10, past a pressure gauge 12 to the nozzle housing 14. The nozzle housing 14 has a plurality of holes 16 placed around its periphery. A collar 18 is connected to the water supply and distributes the water around the nozzle housing so that it will pass through the holes 16. The controlled quantity of water passing into the nozzle forms a water vapor through which the dry insulation must pass. The valve and pressure gauge permit a control of the water to provide a selective prewetting of the dry fiber insulation. The water pressure is normally adjusted somewhere in the range of to 50 p.s.i. An operating pressure of 30 p.s.i. has been found to be quite adequate for securing dust control with conventional fiber insulation.

Optimum results are obtained when the internal Water mist assembly is placed about 8" from the exit of the nozzle. However, acceptable results can be secured by placing the water mist as near as 2" from the exit of the nozzle and as far as 12" from the exit of the nozzle.

The second water injection assembly 20 is positioned on the end of the nozzle housing 14. This assembly also has a water supply hose 22, a control valve 24, and pressure gauge 26. The water passes into a collar 28 which distributes the water around the exit periphery of the nozzle. The water then exits from the collar through apertures 30 which are equally spaced around the periphery of the collar. Normally the apertures 30 direct the water in a direction parallel to the movement of the fiber insulation so that the water forms an envelope around the insulation. It is possible that certain of the apertures 30 may be adjusted to direct the water into the stream of the fiber insulation. This will provide an additional wetting of the fiber insulation, not particularly for dust control, but to provide the fiber insulation with the adhesion necessary to secure a buildup of the fiber on the structure being coated. The water injection assembly 20 is used primarily to control the distribution of the fiber insulation and provide the necessary Wetting of the fiber insulation so that it will have suflicient adhesion to build up to thicknesses upward of 12". The

assembly 20 may have the water pressure adjusted in a range of 10 to p.s.i., but the optimum operating pressure is normally 20 p.s.i. with most conventional fiber insulations.

While the invention has been shown and described as embodied in certain structural details, it should be understood that this is primarily for the purpose of illustrating the principles of the invention and that many modifications and changes may be made in the construction of the apparatus within the spirit and scope of the invention.

I claim:

1. The method of applying spray fiber insulation comprising the steps of: supplying the fiber insulation in a dry moving state to a nozzle structure, using water which is substantially below its boiling point to form a water curtain to prewet the fiber insulation to eliminate a dust problem, discharging the fiber insulation from the nozzle structure and directing Water along a parallel path with the insulation and around the periphery of the discharged insulation to provide the necessary wetting of the insulation to permit it to adhere and build up to the desired thickness.

2. A nozzle structure comprising an entrance opening and an exit opening, means supplying material to the entrance opening, means positioned between the entrance opening and the exit opening providing a fluid curtain through which the supplied material must pass said means comprising, a series of holes circumferentially spaced around the interior of the nozzle structure, means forcing fluid substantially below its boiling point through the plurality of holes to form the fluid curtain, and means near the exit opening of the nozzle to provide a fluid envelope extending from the nozzle and passing around the periphery of the material being discharged from the nozzle and comprising, a series of holes circumferentially spaced around the exit of the nozzle and means forcing fluid through these holes to form the fluid envelope.

References Cited UNITED STATES PATENTS 2,437,042 3/1948 Prosser et al. 239-428 2,747,934 5/1956 Fisher 239-428 X 3,012,732 12/1961 Kempthorne 239-428 X 3,229,850 1/1966 Gartner 239291 X M. HENSON WOOD, JR., Primary Examiner MICHAEL Y. MAR, Assistant Examiner U.S. Cl. X.R. 

